If you are updating your app for iPhone 5 and iPod touch (5th generation), you must provide additional screenshots to support the new screen dimensions for the App Store.
The new screenshot dimensions are:
640 x 1136 (portrait)
640 x 1096 (portrait)
1136 x 640 (landscape)
1136 x 600 (landscape)
To deliver new screenshots, go to the Version Details page in the Manage Your Applications module on iTunes Connect.
If you deliver a new app binary that takes advantage of the new screen size for iPhone 5 or iPod touch (5th generation) without screenshots in the new dimensions, the status of your app will change to Missing Screenshot. Your app will not be reviewed until you upload screenshots with the correct dimensions. You will also need to upload screenshots for any added localizations you have set up on iTunes Connect.